#include <learnopengl/shader_s.h>
#include <GLFW/glfw3.h>

void framebuffer_size_callback(GLFWwindow *window, int width, int height) {
    glViewport(0, 0, width, height);
}

int WinMain(HINSTANCE hInstance, HINSTANCE hPrevInstance, LPSTR lpCmdLine, int nShowCmd) {
    glfwInit();

    glfwInitHint(GLFW_CONTEXT_VERSION_MAJOR, 3);
    glfwInitHint(GLFW_CONTEXT_VERSION_MINOR, 3);
    glfwInitHint(GLFW_OPENGL_PROFILE, GLFW_OPENGL_CORE_PROFILE);

    GLFWwindow *window = glfwCreateWindow(800, 600, "shaders class", NULL, NULL);

    glfwMakeContextCurrent(window);
    glfwSetFramebufferSizeCallback(window, framebuffer_size_callback);

    if (!gladLoadGLLoader((GLADloadproc)glfwGetProcAddress))
    {
        std::cout << "Failed to initialize GLAD" << std::endl;
        return -1;
    }

    Shader ourShader("shader.vs", "shader.fs");

    float vertices[] = {
        0.5f, -0.5f, 0.0f,  1.0f, 0.0f, 0.0f,
        -0.5f, -0.5f, 0.0f, 0.0f, 1.0f, 0.0f,
        0.0f, 0.5f, 0.0f, 0.0f, 0.0f, 1.0f
    };

    unsigned int VBO, VAO;
    glGenVertexArrays(1, &VAO);
    glGenBuffers(1, &VBO);

    glBindVertexArray(VAO);
    
    glBindBuffer(GL_ARRAY_BUFFER, VBO);
    glBufferData(GL_ARRAY_BUFFER, sizeof(vertices), vertices, GL_STATIC_DRAW);


    // position attribute
    glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 6 * sizeof(float), (void*)0);
    glEnableVertexAttribArray(0);
    // color attribute
    glVertexAttribPointer(1, 3, GL_FLOAT, GL_FALSE, 6 * sizeof(float), (void*)(3 * sizeof(float)));
    glEnableVertexAttribArray(1);

    // render loop
    // -----------
    while (!glfwWindowShouldClose(window))
    {

        // render
        // ------
        glClearColor(0.2f, 0.3f, 0.3f, 1.0f);
        glClear(GL_COLOR_BUFFER_BIT);

        // render the triangle
        ourShader.use();
        glBindVertexArray(VAO);
        glDrawArrays(GL_TRIANGLES, 0, 3);

        // glfw: swap buffers and poll IO events (keys pressed/released, mouse moved etc.)
        // -------------------------------------------------------------------------------
        glfwSwapBuffers(window);
        glfwPollEvents();
    }

    // optional: de-allocate all resources once they've outlived their purpose:
    // ------------------------------------------------------------------------
    glDeleteVertexArrays(1, &VAO);
    glDeleteBuffers(1, &VBO);

    // glfw: terminate, clearing all previously allocated GLFW resources.
    // ------------------------------------------------------------------
    glfwTerminate();
    return 0;
}